| 摘要 |
1,147,420. Transistors. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 14 March, 1966 [23 July, 1965; 6 Aug., 1965], No. 50939/68. Divided out of 1,146,600. Heading H1K. A planar transistor has emitter and base regions of a smaller lateral area than a collector region and connected to metallic electrode areas overlying the collector region on an insulating layer. A screening layer is provided between one of the electrode areas and the collector region and is interconnected to the other electrode area by at least one metallic stripe extending over the insulating layer. The screening layer, which is separated from the overlying electrode area by the insulating layer, is a metal layer isolated from the collector region by insulation formed between them. The two embodiments described are NPN silicon transistors. One of these has its base electrode screened from the collector and is to be used in a common emitter emplifier and the other has its emitter electrode screened and is to be used in grounded base configuration. In both an N-type wafer is first provided with boron-doped base region 3 by diffusion through an apertured oxide layer and subsequently with two partial emitter regions 2 by indiffusion of phosphorus. In the embodiment shown screening layer 108 is formed on the oxide layer and is covered by an insulating layer 109 of photo-resist, lacquer or silicon oxide. The base 6 and emitter 5 electrode areas are then formed at the same time as the stripe 11 interconnecting the screening layer with the base electrode area. In the other embodiment (Figs. 11 and 12, not shown) a screening layer (128) lies under the emitter electrode area (5) and is connected to the base contact area (6) by fingers (17) and interconnecting stripes (27) which are kept in a straight line to keep the output shunt capacitance low. The transistors are completed by the provision of collector electrodes and by encapsulation. The Specification also describes but does not claim a construction like that shown (Fig. 9) but wherein the metal screening layer is replaced by semi-conductor region of opposite conductivity type to the collector region and formed in the surface thereof. A similar construction is described corresponding to Fig. 11 (not shown) and is claimed in the parent Specification. |
